It is well known that pathogens and immune deficiency are the major causes of various diseases. The human body is frequently invaded by pathogens and damaged by tumors. Therefore, immunity is necessary in protecting the human body from various infections and damages. Many vaccines currently used induce specific immune responses through subcutaneous and intramuscular injections and help the body survive the disease. However, the injections can only induce systemic immune responses but not mucosal immune responses. The injected vaccine fails to treat and prevent those pathogens transmitted through mucosa. Actually many diseases are transmitted through mucosa, for example, HIV.